Oscillometric Pulse Research Articles

P214 PREDICTION OF AMBULATORY BRACHIAL CUFF-BASED OSCILLOMETRIC PULSE WAVE VELOCITY USING A NOVEL METHOD FOR ESTIMATING TOTAL ARTERIAL COMPLIANCE

Background and Objective: Total arterial compliance (Ct) serves as a critical determinant of arterial hemodynamics, providing insights into the mechanical and structural characteristics of large arteries and influencing ventricular-arterial coupling. To estimate Ct, we developed a method utilizing data from 24-hour ambulatory blood pressure monitoring (24-h ABPM) recordings. Our objective is to evaluate the reliability of Ct in estimating oscillometric pulse wave velocity (oPWV), with the potential to eliminate the requirement for additional oPWV measurements. Methods: A cross-sectional study was conducted, involving 162 patients who underwent 24-h ABPM, resulting in a total of 8,113 blood pressure (BP) recordings. oPWV was measured during 24-h ABPM using a Custo Screen 310 device (Custo, Ottobrunn, Germany), which has been validated. Ct was estimated employing a two-element Windkessel model based on mean systolic pressure. The formula utilized for Ct estimation was Ct/BSA= (38/PPth)×(4/5)×(Td/T)-(3/7), where BSA denotes body surface area, Td represents diastolic time, T signifies the cardiac period, and PPth denotes theoretical pulse pressure. A linear regression model (LRM) was developed to estimate oPWV from Ct. Results: Among the participants, 55.1% were men, with an average age of 55.7±16.2 years and a body mass index of 27.4±3.7 kg/m2. The analyzed records revealed an average systolic blood pressure of 125.6±18.7 mmHg, diastolic blood pressure of 79.5±12.2 mmHg, heart rate of 71.0±12.2 beats per minute, Ct of 0.9±0.3 mL/mmHg, and oPWV of 7.2±1.8 m/s. The best predictive model (R2=0.42; r=0.65) for oPWV was based on the ratio of systolic time (Ts) to Ct as follows: oPWV=3.3 × 6.0 ×[Ts/(Ct/BSA)]. Indexed Ct demonstrated an inverse relationship with oPWV (Figure). Residuals analysis confirmed compliance with assumptions. Conclusions: The Ts/Ct ratio inversely predicts oPWV, indicating an inverse relationship between Ct and oPWV in this population. These findings suggest that estimated Ct has the potential to replace oPWV in clinical practice for cardiovascular risk stratification.

P209 A TEAM-BASED APPROACH TO MANAGE BLOOD PRESSURE BETWEEN COMMUNITY PHARMACISTS AND PRIMARY HEALTH CARE PHYSICIANS BY MEANS OF VASCULAR AGE (RIESCO/TOGETHER)

Background and Objective: Estimating arterial stiffness in Community Farmacies (CPh) has been shown to improve hypertension (HTN) management in Portugal, Austria and Spain. TOGETHER aims to evaluate whether empowering hypertensive subjects by determining arterial stiffness in CPh increases HTN control, establishing paths of lasting cooperation between Primary Care (PC) doctors and CPh. Methods: TOGETHER is a cluster-randomized, prospective study in Portugal, Austria and Spain. All consecutive expected 1260 subjects entering CPh will be offered BP measurement and ambulatory BP monitoring (ABPM) for those with high values. CPh will be randomly grouped into a usual care arm (health education associated with HTN and communication of the results to PC). In the experimental care group, early vascular aging (EVA) will additionally be assessed estimating oscillometric pulse wave velocity. The therapeutic options of EVA will be explained to patients/PC. HTN will be treated by PC according to usual clinical practice. A second evaluation with ABPM will be performed after 6 months and HTN control will be compared between the arms. The degree of patient-doctor interaction will be determined through validated surveys. Results Five fundamental unmet needs will be addressed by TOGETHER: 1) lack of HTN screening programs; 2) Implementation of the simpler and more informative EVA concept (“Your arteries are 10 years older than you”); 3) understanding CV risk on an individual basis (individual EVA) should improve patient adherence and reduce physician inertia; 4) Implementation of health educational programs, combined with the concept of EVA; 5) Higher collaboration and development of a team-based approach to HTN care between CPh and PC. Conclusions: The complementary organizational settings and strengths of CPh and PC will allow TOGETHER to create new strategies for early identification and intervention in HTN, ranging from lifestyle to medical treatment, taking social, economic, and behavioral aspects into account.

Arteriovenous Oscillometric Plethysmography for Fistula Functional Testing.

The aim of the presented prospective observational study was to evaluate the effect of fistula flow on peripheral wave morphology and pulse wave velocity by means of the oscillometric Vicorder®-device with the purpose of fistula surveillance. Digitized and normalized curves of 53 haemodialysis patients at the fistula and non-fistula arm were analysed. Slope parameters and the areas under the curve of characteristic sections of pulse waves as well as the power spectrum of the pulse waves and their first and second derivatives were computed. Furthermore, the amplitude of volumetric change (AMP) was assessed. Duplex sonography served as a reference method. In the comprehensive set of novel pulse wave parameters significant inter-arm differences were demonstrated and a significant delay of the systolic maximum at the fistula arm in comparison to the non-fistula arm (204 ± 3.4 vs. 162 ± 5.3 ms, p < 0.001) was proven. Unexpectedly, pulse wave velocity apparently did not differ between both arms (7.85 vs. 8.05 m/s at the fistula/non-fistula side, p = 0.942). The inter-arm differences of the slope parameters were more pronounced in forearm than in upper arm fistulas. Finally, we showed that the inter-arm difference of AMP correlated with volume flow (r = 0.326 with p = 0.017). Pulse waves as assessed by oscillometric pulse wave analysis have distinct features at fistula and non-fistula arms. This is due to enhanced arteriovenous flow, i.e. in both the brachial artery and the fistula vein. The analysis of those alterations has the potential to assess fistula function.

Comparison of cardiac output estimates obtained from the Antares oscillometric pulse wave analysis algorithm and from Doppler transthoracic echocardiography.

In cardiology, cardiac output (CO) is an important parameter for assessing cardiac function. While invasive thermodilution procedures are the gold standard for CO assessment, transthoracic Doppler echocardiography (TTE) has become the established method for routine CO assessment in daily clinical practice. However, a demand persists for non-invasive approaches, including oscillometric pulse wave analysis (PWA), to enhance the accuracy of CO estimation, reduce complications associated with invasive procedures, and facilitate its application in non-intensive care settings. Here, we aimed to compare the TTE and oscillometric PWA algorithm Antares for a non-invasive estimation of CO. Non-invasive CO data obtained by two-dimensional TTE were compared with those from an oscillometric blood pressure device (custo med GmbH, Ottobrunn, Germany) using the integrated algorithm Antares (Redwave Medical GmbH, Jena, Germany). In total, 59 patients undergoing elective cardiac catheterization for clinical reasons (71±10 years old, 76% males) were included. Agreement between both CO measures were assessed by Bland-Altman analysis, Student's t-test, and Pearson correlations. The mean difference in CO was 0.04 ± 1.03 l/min (95% confidence interval for the mean difference: -0.23 to 0.30 l/min) for the overall group, with lower and upper limits of agreement at -1.98 and 2.05 l/min, respectively. There was no statistically significant difference in means between both CO measures (P = 0.785). Statistically significant correlations between TTE and Antares CO were observed in the entire cohort (r = 0.705, P<0.001) as well as in female (r = 0.802, P<0.001) and male patients (r = 0.669, P<0.001). The oscillometric PWA algorithm Antares and established TTE for a non-invasive estimation of CO are highly correlated in male and female patients, with no statistically significant difference between both approaches. Future validation studies of the Antares CO are necessary before a clinical application can be considered.

CARDIAC OUTPUT ESTIMATION: PULSE WAVE ANALYSIS (ANTARES) HIGHLY CORRELATES TO ECHOCARDIOGRAPHY ASSESSMENT

Objective: Evaluation of cardiac output (CO) is crucial for understanding cardiac function and diagnosis of heart failure. While invasive thermodilution procedures serve as the gold standard for CO assessment, routine clinical practice has widely adopted transthoracic Doppler echocardiography (TTE) as the established non-invasive method. Nevertheless, there is a persistent demand for alternative non-invasive approaches, aiming to improve the efficiency of CO estimation, mitigate complications associated with invasive methods, and extend its application to non-intensive care settings, all of which potentially can be offered by oscillometric pulse wave analysis (PWA). This study aims to compare the non-invasive estimation of CO using TTE and the oscillometric PWA algorithm Antares. Design and method: We compared non-invasive cardiac output data obtained through two-dimensional transthoracic echocardiography with data obtained from an oscillometric blood pressure device (custo med GmbH, Ottobrunn, Germany) utilizing the integrated Antares algorithm (Redwave Medical GmbH, Jena, Germany). A total of 59 patients, undergoing elective cardiac catheterization for clinical reasons, were included in the study (mean age 71±10 years, 24% females), but only echocardiography-data with CO were used for analysis. Agreement between the two CO measurement methods (TTE versus Antares) was evaluated through Bland-Altman analysis, Student's t-test, and Pearson correlations. Results: The mean difference in CO was 0.04 ± 1.03 l/min. No statistically significant difference in means was observed between the two CO measurement methods. Significant correlations between transthoracic echocardiography (TTE) and Antares CO were evident in the overall population (r=0.71), as well as in both, female (r=0.80) and male patients (r=0.67; all p&lt;0.001). Conclusions: The oscillometric PWA algorithm Antares and the established TTE exhibit strong correlations for non-invasive CO estimation in both male and female patients, with no statistically significant differences between the two approaches. This study opens the door to a valid and simple detection of heart failure that is seamlessly integrated into a quick and easy-to-perform upper arm blood pressure measurement.

VASCULAR AGE AS A KEY FOR A TEAM-BASED APPROACH TO MANAGE BLOOD PRESSURE AND CARDIOVASCULAR RISK BETWEEN COMMUNITY PHARMACISTS AND PRIMARY HEALTH CARE CENTERS (TOGETHER)

Objective: Hypertension (HTN) is the main cause of premature death worldide. Previous studies in Portugal, Austria and Spain have shown that estimating arterial stiffness in Community Farmacies (CPh) improves its management. The main objective is to evaluate whether empowering hypertensive subjects by determining arterial stiffness in CPh increases the rate of HTN control. Secondary objective is to establish paths of lasting cooperation between Primary Care (PC) doctors and CPh. Design and method: TOGETHER is a randomized study in Portugal, Austria and Spain. All consecutive expected 1260 subjects entering CPh will be offered blood pressure measurement and ambulatory blood pressure monitoring (ABPM) for those cases with high values. 140 CPh will be randomly grouped into a usual care arm (health education associated with HTN and communication of the results to PC). In the experimental care group, early vascular aging (EVA) will additionally be assessed estimating oscillometric pulse wave velocity. The concept and therapeutic options of EVA will be explained to patients and PC. HTN will be treated by PC according to usual clinical practice. After 6 months a second evaluation with ABPM will be performed and HTN control will be compared between the two arms. The degree of patient-doctor interaction and economic implications will be determined through validated surveys. Results: TOGETHER will address five fundamental unmet needs: 1) lack of HTN screening programs; 2) the concept of cardiovascular risk is difficult to understand. The EVA concept (“Your arteries are 10 years older than you”) is simple and more informative; 3) understanding CV risk on an individual basis (individual EVA) should improve patient adherence and reduce physician inertia; 4) TOGETHER will implement health educational programs, combined with the concept of EVA; 5) there is an objective need to improve collaboration and develop a team-based approach to HTN care between CPh and PC. Conclusions: The complementary strengths and organizational settings of CPh and PC will allow TOGETHER to create new strategies for early identification and intervention in HTN, ranging from lifestyle to medical treatment, taking social, economic, and behavioral aspects into account.

Abstract 13220: Independent Effects of Baseline Pulse Wave Velocity versus Advancing Age on Changes in Arterial Stiffness Over Time

Introduction: While arterial stiffness (AS) is a known marker of vascular ageing that prognosticates cardiovascular disease (CVD), prospective analyses of AS evolution alongside chronological age are necessary to understand factors that drive progressive AS. Using pulse wave velocity (PWV) we investigated the impact of baseline factors in predicting PWV changes over a 5-year period. Hypothesis: We hypothesized that certain baseline factors in older Asian adults are predictive of PWV trajectories later in life independent of chronological age. Methods: Participants without CVD from a community-based cohort had their clinical risk factors collected prospectively, and PWV (m/s) measured using a cuff-based oscillometric pulse wave analysis machine at baseline and 5-year timepoint. Results: This analysis included 159 participants (41.5% women, mean age 67.7 ± 10.2 years). ΔPWV (2.19 ± 2.25), the 5-year change in PWV, was associated with baseline PWV (β = -0.687, p &lt; 0.001), age (β = 0.084, p &lt; 0.001), hypertension (β=0.763, p = 0.033), weight (β = -0.042, p = 0.018) and waist circumference (β = -0.045, p = 0.018). Gender, body mass index, dyslipidemia, diabetes mellitus and lifetime smoking status were not significantly associated with ΔPWV. ΔPWV was independently associated with baseline PWV (β = -1.17, 95% CI -1.65 - -0.70, p &lt; 0.001) and age (β = 0.144, 95% CI 0.09 - 0.20, p &lt; 0.001) adjusting for weight, waist circumference and hypertension, with insignificant interaction between baseline PWV and age (p = 0.431). Participants with increases in PWV after 5 years, compared to those without PWV increase, had lower PWV (8.52 ± 1.81 vs 11.10 ± 2.44) at baseline. Conclusions: Baseline PWV was associated with changes in AS over a 5-year period independent of age and clinical risk factors. The inverse relationship between baseline PWV and ΔPWV may suggest plateauing of PWV increases at higher baseline PWV levels. In addition, high baseline PWV may not predict worsening of AS later in life.

Abstract 13041: Effects of Parity on Arterial Stiffness Persists Into Old Age, Independent of Chronological Ageing

Introduction: Persistent effects of reproductive factors on vascular ageing, over chronological ageing, as examined through objective measurements of arterial stiffness, are rarely studied. Hypothesis: We hypothesized that the effects of parity and maternal age at first birth (AFB) on vascular ageing will persist over time independent of chronological ageing, in older Asian women. Methods: Among a community-based cohort of older Asian adults without cardiovascular disease, we prospectively studied demographics, parity, AFB, and cardiovascular risk factors, at baseline and 5-year examination timepoints. Arterial stiffness was measured through pulse wave velocity (PWV) using a cuff-based auscultatoric oscillometric pulse wave analysis machine. Results: 170 women (baseline mean age 60.76±13.75 years) were included. Parity ranged from 0 to 8 (mean parity 2±1.3). AFB ranged from 18 to 44 (mean age 28±4.4) years. By regression, univariate determinants of 5-year PWV were parity (β=0.491, p=&lt;.001), αFB (β=-0.107, p=.011), baseline age (β=3.884, p=&lt;.001), body mass index (βμΙ) (β=0.147, p=.006), waist circumference (β=0.076, p=&lt;.001), diabetes (β=1.681, p=&lt;.004), hypertension (β=2.383, p=&lt;.001), dyslipidemia (β=2.220, p=&lt;.001), 5-year age (β=3.886, p=&lt;.001),waist circumference (β=0.085, p=&lt;.001), diabetes (β=1.723, p=.001), hypertension (β=2.485, p=&lt;.001). Based on multivariate regression, parity (β=0.345, 95% CI 0.105, 0.586, p=.005), but not AFB, was independently associated with 5-year PWV, independent of age. Conclusions: Parity and AFB correlated with PWV, a marker of arterial stiffness, in old age in Asian women. Accounting for chronological ageing and clinical factors across 5 years, parity exerted a persistent independent effect on arterial stiffness in older women. Other biological factors surrounding parity in these women apart from traditional cardiovascular risk factors may explain these observations.

Hybrid Deep Morpho-Temporal Framework for Oscillometric Blood Pressure Measurement.

Oscillometric blood pressure (BP) measurement devices are widely utilized as the primary automated BP measurement tools in non-specialist environments. However, their accuracy and reliability vary under different settings and for different age groups and health conditions. An essential constraint of current oscillometric BP measurement devices is their analysis algorithms' incapacity to capture the BP information encoded in the pattern of recorded oscillometric pulses to its fullest extent. In this paper, we propose a new 2D oscillometric data representation that enables a full characterization of arterial system and empowers the application of deep learning to extract the most informative features correlated with BP. A hybrid convolutional-recurrent neural network was developed to capture the oscillometric pulses morphological information as well as their temporal evolution over the cuff deflation period from the 2D structure, and estimate BP. The performance of the proposed method was verified on three oscillometric databases collected from the wrist and upper arms of 245 individuals. It was found that it achieves a mean error and a standard deviation of error of as low as 0.08 mmHg and 2.4 mmHg in the estimation of systolic BP, and 0.04 mmHg and 2.2 mmHg in the estimation of diastolic BP, respectively. Our proposed method outperformed the state-of-the-art techniques and satisfied the current international standards for BP monitors by a wide margin. The proposed method shows promise toward robust and objective BP estimation in a variety of patients and monitoring situations.

Technical evaluation of a simulator for accurate reproduction of oscillometric blood pressure pulses, providing traceability for automated oscillometric sphygmomanometers

Oscillometric blood pressure measurement devices are not directly traceable to primary standards. Currently, device accuracy is measured by comparison between a sample device and reference measurements in a clinical trial. We researched in this study the potential for an alternative evaluation with a simulator. Our research simulator was studied for repeatability and accuracy in delivering simulated blood pressure pulses. Clinical cuff pressure measurements were obtained, along with simultaneous recordings of oscillometric pulse waveforms, spanning the clinical range of cuff pressures, pulse intervals and pulse shapes. Oscillometric pulse peak amplitudes ranged from 1.1 to 3.6 mmHg. Simulated repeatability results showed an average Standard Deviation (SD) for pulse peaks of 0.018 mmHg; 1.0% of peak amplitudes. Comparing simulated pulse shapes, the average repeat SD was 0.015 mmHg; 0.8% of the normalised pulse shapes. The simulated accuracy results had a mean error of − 0.014 ± 0.042 mmHg with a mean accuracy of 97.8%. For pulse shape the corresponding values were − 0.104 ± 0.071 mmHg with a mean accuracy of 95.4%. The correlation between the reference and simulated pulse shapes ranged from 0.991 to 0.996 (all p < 0.00003), with a mean 0.994. We conclude that oscillometric pulses can be reproduced with high repeatability and high accuracy with our research simulator. The extended uncertainty U(p sim ) = 0.3 mmHg for the simulated pulses is dominated by the uncertainty (64%) of the clinical reference data. These results underpin the potential of the simulator to become a secondary standard for millions of oscillometric sphygmomanometers.

Evaluation of primary hemodynamic parameters using in-house developed flexible microstructured pressure sensor

Noninvasive measurement of arterial pulse provides information about the heart condition through the evaluation of primary hemodynamic parameters such as blood pressure (BP), pulse rate (PR), and pulse regularity. Moreover, BP is one of the most important biomarkers of cardiovascular disease, mainly hypertension. To prevent this, accurate measurement of BP becomes necessary. Currently, flexible pressure sensors have drawn a lot of interest due to their prospective applications in wearable devices for healthcare monitoring. We have collected the human oscillometric pulse by a polymer-based flexible capacitive pressure sensor and calculated the BP as well as PR using the maximum amplitude algorithm. The results are compared with a pre-calibrated oscillometric BP monitor available in the market. Based on the error criteria, the device followed the universal standard. In addition, the flexibility and high accuracy of the device result in the assessment of the possible medical applications, including abnormal pulse rates such as tachycardia or bradycardia and irregular heart rhythm such as cardiac arrhythmia.

Effect of high intensity interval training on arterial stiffness in obese hypertensive women: a randomized controlled trial.

High-intensity interval training (HIIT) has been linked to a lower risk of cardiovascular disease and mortality. The study's overarching goal is to evaluate the impact of HIIT on arterial stiffness in obese hypertensive women. Sixty obese hypertensive women aged between 40-50 years were randomized to group A (Intervention group, n = 30) or group B (Control group, n = 30). Intervention group received HIIT (4 minutes of cycling at 85-90% of peak HR interspersed with 3-minute active recovery time at 60 - 70% of peak HR, three times per week). Arteriovenous stiffness indicators, the augmentation index corrected for heart rate 75 (AIx@75HR), and oscillometric pulse wave velocity (o-PWV), as well as cardio-metabolic parameters, were assessed before and after 12 weeks of treatment. Finding between-group analysis showed a significant difference in AIx@75HR (95% CI: -8.45 to 0.30) , o-PWV ( 95% CI: -1.14 to 0.15), total cholesterol, (95% CI: -31.25 to -1.12), HDL-cholesterol (95% CI: 8.92 to 0.94), LDL-cholesterol (95% CI: -25.35 to -0.06) , and triglycerides (95% CI: -53.58 to -2.51). High-intensity interval training for 12 weeks has a favorable effect on arterial stiffness in obese hypertensive women and lowers associated cardio-metabolic risk factors.

Invasive validation of the Antares algorithm for determining central blood pressure based on upper arm oscillometric pulse waves in patients with type 2 diabetes

IntroductionAntares is a pulse wave analysis (PWA) algorithm designed to allow a non-invasive estimation of central (aortic) blood pressure (cBP) using automated oscillometric blood pressure (BP) devices. Diabetes may affect...

Bradycardia may determine blood-pressure variability: results from real life office measurements of over half a million members of a large health maintenance organization in Israel.

Objective: Historically, guidelines for blood pressure (BP) measurement recommended adjusting the cuff deflation rate to the patient’s heart rate (2-3 mmHg per heartbeat). Current guidelines recommend a fixed cuff deflation rate of 2 mmHg/sec. This translates to that, on average, the number of Korotkoff sounds (or oscillometric pulse waves) on which BP measurement is based is larger in patients with higher compared with lower pulse rate. It follows that the precision (and accuracy) of BP may be compromised in patients with lower heart rate, leading to higher intra-individual BP variability. In this study, we assess the association between heart rate and BP variability. Design and Methods: Retrospective analysis of BP measurements of patients in a large health maintenance organization database. All BP measurements in adult patients with corresponding heart rate documentation were reviewed. For each heart rate category (6 categories between 40 and 99 beats per minute), all patients with at least 3 BP readings within that category were included. In each category, systolic and diastolic BP coefficient of variance (corrected for sample size) was plotted against the pulse category. Results: There were 551,595 unique patients with at least 3 BP measurements within a heart rate category (a total of 4,760,000 measurements) and 860,522 groups of 3 measurements or more per patient within a heart rate category. BP normalized coefficient of variance was inversely related to heart rate, ranging 0.0043 to 0.0003 (systolic), and 0.0024 to 0.0002 (diastolic), for the lowest to highest heart rate category, respectively. These results were consistent when sensitivity analyses were done with age below and above 60 years, gender, diabetes, kidney disease, treatment with β-blockers, calcium channel blockers, or no treatment. Conclusions: BP variability is inversely associated with heart rate, especially in lower heart rate, likely reflecting less precise BP measurements where the “sample size” of heart beats is small. The observed effect compromising precision might be accompanied by a concomitant reduced accuracy of BP measurement which is another theoretical implication of a smaller “sample size”, leading to a systematic bias towards measuring lower and higher than real systolic and diastolic BP respectively.

Proposing a Method to Measure NIBP Parameters Using PPG Signal and Analyzing the Morphology of Oscillometric

The demand for monitoring non-invasive blood pressure (NIBP) parameters in health facilities for medical examination and treatment, specifically self-monitoring at home is significantly increasing. The measurement methods are based on many different techniques. However, the accuracy and stability of the measurement results from these techniques are still controversial. In this study, we proposed a novel method to measure the two most important parameters in NIBP measurement by combining two techniques: observing the Photoplethysmogram (PPG) signal to determine the Systolic Blood Pressure (SBP) and analyzing the changes of the morphology of oscillometric pulses to determine the Mean Arterial Pressure (MAP). The results were attained from 30 volunteers by using the proposed model and two commercial NIBP devices from iChoice and Omron for comparison. The measuring results of the proposed model have shown a good correlation and high stability of SBP, DBP (Diastolic Blood Pressure) and MAP measurements compared to the current techniques, expressed by the correlation of determination R2, the mean difference of proposed model to each commercial device, NIBPP – NIBPiC, NIBPP – NIBPO, and the mean (SD) between measurement results of volunteers.

The Oscillometric Pulse Wave Analysis Is Useful in Evaluating the Arterial Stiffness of Obese Children with Relevant Cardiometabolic Risks.

Early detection of all complications of childhood obesity is imperative in order to minimize effects. Obesity causes vascular disruptions, including early increased arterial stiffness and high blood pressure. This study’s aim is to assess the reliability of pulse wave analysis (PWA) in obese children and how additional risk factors influence the evaluated parameters. We analyzed 55 children aged 6–18 years old by measuring their pulse wave velocity (PWV), augmentation index (AIx), peripheral blood pressure (SBP, DBP), heart rate, central blood pressure (cSBP, cDBP) and central pulse pressure (cPP). We used the oscillometric IEM Mobil-O-Graph and performed a single-point brachial measurement. The subjects were divided into two groups: obese (n = 30) and normal-weight (n = 25) and were clinically and anamnestically assessed. BMI and waist circumference are significantly correlated to higher values for PWV, SBP, DBP, cSBP, and cDBP. Weight significantly predicts PWV, SBP, DBP and cPP. The risk factors that significantly influence the PWA and BP values are: a cardiometabolically risky pregnancy (higher PWV, AIx, SBP), active and passive smoking (higher PWV, SBP, cSBP, cDBP), sleep deprivation (higher PWV, SBP, cSBP) and sedentariness (higher PWV, AIx, peripheral and central BP). We conclude that obese children with specific additional cardiometabolic risk factors present increased arterial stiffness and higher blood pressure values.

DeepPAD: Detection of Peripheral Arterial Disease Using Deep Learning

Peripheral arterial disease (PAD) is a common circulatory disease caused by the deposition of fatty plaque on the arterial wall. Early detection and treatment of PAD are essential in preventing further cardiovascular and health complications. It was recently shown that PAD can be detected using an oscillometric device by characterizing the peripheral arterial system at different externally applied cuff pressures. However, the extraction of the complex relationship between the pattern of the oscillometric waveforms and the presence of PAD remained challenging. This study proposes a novel deep learning approach for the detection of PAD by capturing the peripheral arterial system behavior at different cuff pressures. The periodic pattern of the oscillometric pulses and their variations as a function of cuff pressure were modeled using a deep recurrent neural network based on the bidirectional long short-term memory and attention mechanism. The proposed model was evaluated by analyzing the raw oscillometric pulses as well as statistical features on data collected from 33 individuals (14 PAD and 19 normal). The results show a high accuracy of up to 94.8%, a sensitivity of up to 90.0%, and a specificity of up to 97.4% in detecting PAD. The proposed method provides new opportunities for noninvasive cardiovascular screening and early detection of PAD using the oscillometric principle.

Measurement of Ankle Brachial Index with Oscillometric Method for Early Detection of Peripheral Artery Disease

Peripheral Arterial Disease (PAD) is a blood vessel disease caused by blockage or plaque accumulation around the artery walls. PAD is included in the category of diseases that are often diagnosed too late and affect more severe cases, such as the death of certain tissues or body parts. The Ankle Brachial Index (ABI) is an accurate non-invasive method for diagnosing PAD, in practice, ABI is usually performed in certain hospitals and is still difficult to find due to limited tools. Therefore, a tool is made that can detect the condition of a person's PAD based on the ABI value. The tool is made using two MPX5050GP sensors to detect oscillometric pulses, a DC pump and solenoid valve as an actuator to pump and deflate the cuff, ADS1115 as an external ADC to increase the accuracy of sensor readings, as well as an LCD and buzzer as tool indicators. The output is displayed in the form of a print out from a thermal printer, with an emergency stop that functions as a safety system to power off the supply when a failure occurs in the measurement process. Oscillometric method is used to detect systolic and diastolic pressure. The accuracy of the tool is 95.5%. This accuracy result is obtained by comparing the readings of systolic and diastolic values using a sphygmomanometer which is commonly used.

Oscillometric evaluation of the effects of cardiotoxic chemotherapeutic agents on vascular stiffness.

Several clinical studies have demonstrated that arterial stiffness is an early indicator of cardiovascular events. Our study aimed to detect the potential cardiovascular changes using arterial stiffness parameters and compare these changes with echocardiographic aortic stiffness parameters, in cancer patients treated with cardiotoxic chemotherapeutics. Our study is a prospective case-control study. A total of seventy subjects between the ages of 18 and 50 years were included into our study. Thirty of them were newly diagnosed cancer patients and forty constituted the age- and sex-matched control group. Baseline oscillometric arterial and echocardiographic aortic stiffness parameters were measured in all patients. In cancer patients, all of these parameters were measured again, 1 month after chemotherapy protocol was completed. Mean age of the cancer patients was 41.4 ± 5.9 years and mean age of the control group was 39.6 ± 6.6 years (P = 0.258). Before chemotherapy, arterial and aortic stiffness parameters were similar between the study and the control group. After chemotherapy, the oscillometric pulse wave velocity parameter increased compared with the control group and to the prechemotherapy values (P = 0.004 and P < 0.001, respectively). After chemotherapy, the augmentation index parameter increased compared with the control group (P = 0.013). On the other hand, no difference was detected between the groups in terms of echocardiographic aortic stiffness parameters. In newly diagnosed cancer patients treated with cardiotoxic chemotherapeutics, considerable impairment occurs in some of the oscillometric arterial stiffness parameters, while there is no substantial effect on echocardiographic aortic stiffness. Arterial stiffness parameters in these patients might be useful in evaluating subclinical cardiovascular damage.

Feasibility of Calculating Aortic Pulse Wave Velocity from Oscillometric Upper Arm Pulse Waves Using the Antares Algorithm

BackgroundAntares is an algorithm for oscillometric blood pressure (BP) monitors to determine aortic pulse wave velocity (PWV) solely using oscillometric pulse waves without dependence of any other input. The aim of this study is to test Antares PWV for feasibility and whether the known age and blood pressure dependence of PWV can be shown with Antares PWV.MethodsIn total, 259 patients were investigated for PWV as sub-study of the invasive validation of Antares algorithm, of which 219 entered analyses. Non-invasive PWV determination by Antares algorithm, integrated into an oscillometric BP monitor (custo screen 400) was compared to five different ePWV equations based on age, BP, or both. Additionally, in a subset of 27 patients, comparison of ARCSolver PWV algorithm (Mobil-O-Graph) with Antares PWV and ePWV was conducted.ResultsMean differences ± SD between Antares PWV and (A) ePWV (based on age and systolic BP) was − 0.05 ± 1.06 m/s (Spearman’s rank correlation coefficient, rS = 0.805); (B) ePWV (based on age) was − 1.75 ± 1.17 m/s (rS = 0.829); (C) ePWV (based on mean BP) was − 1.35 ± 1.24 m/s (rS = 0.763), and (D) ePWV (based on age and mean BP) was − 1.64 ± 1.22 m/s (rS = 0.810) and − 1.69 ± 1.18 m/s (rS = 0.802). Comparison of Antares PWV with ARCSolver PWV revealed a mean difference of − 0.65 ± 1.31 m/s (rS = 0.854).ConclusionThe Antares algorithm confirmed its feasibility to use an oscillometric BP monitor as a single-point measurement device to calculate aortic PWV with acceptable comparability and high correlation to both estimated PWV and ARCSolver PWV. Antares achieves these results solely based on analysis of waveform features without requiring any secondary input, like BP or age.